Conventionally, in a battle game server, each user's deck is formed by a plurality of battle cards or the like stored for each user, and the battle game server allows a plurality of users to compete with each other based on the total value of the attack strength and defense strength of the deck (for example, see Patent Literature 1). In such a battle game server, the user acquires a battle card by methods such as purchasing the battle card or obtaining the battle card by winning a battle against an opponent.